The present disclosure relates to subject matter contained in priority Japanese Patent Application No. 2001-349813, filed on Nov. 15, 2001, the contents of which is herein expressly incorporated by reference in its entirety.
1. Field of the Invention
The present invention relates to a stop lamp switch which is used for controlling a stop lamp to be lighted only when a brake pedal of a vehicle is pressed and to a method for attaching such a stop lamp switch.
2. Description of Related Art
Recently, the following type of stop lamp switch has been widely used as a stop lamp switch employed for controlling the lighting of a stop lamp. Specifically, when the stop lamp switch is to be attached to an attachment bracket opposing to a brake pedal of a vehicle, a projected length of an operation shaft of the stop lamp switch can be adjusted while directly abutting the operating shaft on the brake pedal. Such a stop lamp switch is intended to ensure a turn-on operation of the stop lamp when the brake pedal is pressed and a turn-off operation of the stop lamp when the brake pedal is no more pressed, regardless of variations in size and shape of the stop lamp switch, its relative position with respect to the brake pedal or the attachment bracket, and the like.
The above-described type of a conventional stop lamp switch has a structure as shown in a longitudinal cross-sectional view of FIG. 9. More specifically, a cover body 3 is connected to a cylindrical case 2 made of an insulating resin with an upper open end, through the engagement between engagement holes 4 and engagement claws 7 to form a stop lamp switch 1. A connector connection part 2b for fitting a connector described below thereto is integrally formed with the case 2 below its bottom wall 2a. Terminal portions 8a of fixed contacts 8 are penetrated through the bottom wall 2a so as to be projected into the connector connection part 2b, whereby the fixed contacts 8 are held at predetermined positions within the case 2. Movable contacts 9, which constitute switch contacts with the fixed contacts 8, are in elastic contact with the fixed contacts 8 on their bottoms by a contact pressure spring 10 interposed between the movable contacts 9 and the bottom wall 2a in a somewhat deflected state.
A cylindrical actuator 11 serves to allow the movable contacts 9 to be in contact with/separate from the fixed contacts 8. The cylindrical actuator 11 is provided so as to be freely slidable in in/out directions to/from the case 2 by fitting a guide rib (not shown) of the actuator 11 into a guide groove (not shown) of the case 2. At the same time, the actuator 11 is always energized by a return spring 12 in such a direction that the actuator 11 is projected from the case 2. The return spring 12 is provided between an engagement wall 11a and the bottom wall 2a of the case 2, where the engagement wall 11a is integrally formed with the actuator 11 so as to divide an inner space of the actuator 11 in two. A cylindrical operating shaft 13 having a head is penetrated through a guide hole 3a of the cover body 3 so as to be connected to one end of the actuator 11 with an engaging spring 14 being interposed therebetween in a displaceable state. More specifically, the engaging spring 14 having an approximately U shape when viewed from a plane is engaged with one end of the actuator 11 so as to perpendicularly cross an opening on the end of the actuator 11. The operating shaft 13 has concave-convex locking portions 13a formed along its axial direction on parts of its outer surface, the parts of the outer surface being opposed to each other in a radial direction. The concave-convex locking portions 13a are forced into a slightly enlarged middle space of the U-shaped engaging spring 14 while spreading the middle space, so that the operating shaft 13 is connected to the actuator 11 with the engaging spring 14 being interposed therebetween.
The engaging spring 14 is brought into elastic contact with the concave-convex locking portions 13a on the both sides due to a restoring force of the middle portion of the engaging spring 14 which is deformed in a spreading direction. The operating shaft 13 can be forced into the actuator 11 against the engagement force of the engaging spring 14 with the concave-convex locking portions 13a. The operating shaft 13 is thus forced into the actuator 11 so as to adjust its projected length from the guide hole 3a of the cover body 3. As a result, a connected length between the actuator 11 and the operating shaft 13 can be adjusted in such a manner to allow the reduction thereof.
The stop lamp switch 1 is attached in the following manner. After a part of the operating shaft 13 and the cover body 3 is inserted into an attachment hole 17a of the attachment bracket 17 which is opposed to a brake pedal of a vehicle, the stop lamp switch 1 is relatively rotated with respect to the attachment bracket 17 so as to engage engaging portions 3b outwardly protruding from both sides of the cover body 3 in its radial direction with the edge of the attachment hole 17a. FIG. 10 is a side view showing a state where the stop lamp switch 1 is attached to the attachment bracket 17 of a vehicle in the above-described manner. A brake pedal 18 is freely turnably provided around a spindle 19 serving as a supporting point. At the same time, the brake pedal 18 is energized to be turned in a right-hand direction of FIG. 10 by a spring 20 so as to be held at a normal position indicated with a solid line in the drawing. More specifically, the spring 20 is set to have a larger spring pressure than the total spring pressure of the contact pressure spring 10 and the return spring 12 of the stop lamp switch 1.
The operating shaft 13 of the stop lamp switch 1 before its attachment is set to have a rather large projected length from the guide hole 3a. In its attachment to a vehicle, the operating shaft 13 is pushed into the cover body 3 until the projected length is reduced to allow the attachment of the operating shaft 13 to the attachment bracket 17 while a tip of the operating shaft 13 is abutting on an abutting face 21 of the brake pedal 18. At this moment, the engagement force between the concave-convex locking portions 13a of the operating shaft 13 and the engaging spring 14 is larger than the spring pressure of the spring 20. Consequently, in the case where the operating shaft 13 is inserted into the attachment hole 17a of the attachment bracket 17, the brake pedal. 18 is pressed by the operating shaft 13 so as to be turned from the position indicated with the solid line in FIG. 10 to the position indicated with a double-chain line against the energizing force of the spring 20. Accordingly, with such a structure, it is not possible to adjust a projected length by inserting the operating shaft 13 into the cover body 3.
In order to solve this problem, the stop lamp switch 1 has been conventionally attached in the following procedure. The operating shaft 13 is penetrated through the attachment hole 17a of the attachment bracket 17 so that its tip abuts on the abutting face 21 of the brake pedal 18 while holding the brake pedal 18 so as not to be moved from the normal position indicated with the solid line in FIG. 10. Thereafter, the stop lamp switch 1 is pushed toward the brake pedal 18.
In the above-described attachment operation, when the operating shaft 13 is pushed against the abutting face 21, the actuator 11, which holds the operating shaft 13 with the engaging spring 14 being interposed therebetween, moves in a downward direction in the drawing from the state shown in FIG. 9 while compressing the return spring 12. As a result, the movable contacts 9 are pushed down to be separated from the fixed contacts 8. Thereafter, once the actuator 11 abuts on the bottom wall 2a of the case 2 through the movable contacts 9, the actuator 11 is no more displaceable. Therefore, the operating shaft 13 is subsequently inserted into the actuator 11 while the concave-convex locking portions 13a are spreading the engaging spring 14 which is in elastic contact therewith. As a result, the engaging portions 3b of the cover body 3 are ready to fit into the attachment hole 17a of the attachment bracket 17. The stop lamp switch 1 is relatively rotated with respect to the attachment bracket 17 in this state so as to be fixed.
In this attachment state, the operating shaft 13 is connected to the actuator 11 at the adjusted relative position with respect to the actuator 11 through the engagement between the concave-convex locking portions 13a and the engaging spring 14. Moreover, the brake pedal 18 is held at the normal position indicated with the solid line shown in FIG. 10 by a larger energizing force of the spring 20 against the energizing force of the contact pressure spring 10 and the return spring 12. Therefore, the movable contacts 9 are held at the position separated from the fixed contacts 8 so that the switch contacts are kept in an OFF state. Then, as shown in FIG. 10, when a connector 22 is fitted to the connector connection part 2b of the case 2, the terminal portions 8a of the fixed contacts 8 are inserted to be connected to a power supply circuit of a stop lamp (not shown) through the connector 22, thereby completing the attachment of the stop lamp switch 1.
When the brake pedal 18 is pressed so as to be displaced to the position indicated with the double-chain line of FIG. 10, the abutting face 21 is separated from the operating shaft 13 so as to cancel the application of a pressure on the operating shaft 13. Thus, the actuator 11 moves while pushing out the operating shaft 13 outside the cover body 3 due to the energizing force of the return spring 12. At the same time, the movable contacts 9 are brought into elastic contact with the fixed contacts 8 due to the energizing force of the contact pressure spring 10, whereby the switch contacts are brought into an ON state. As a result, a power is supplied to a stop lamp via the stop lamp switch 1 in an ON state so as to light the stop lamp.
However, since a projected length of the operating shaft 13 is adjusted upon attachment of the operating shaft 13 to the attachment bracket 17 in the above-described stop lamp switch 1, at least two operators are required; one is for keeping the brake pedal 18 with his (her) hands to hold it at the normal position, and the other is for pushing the stop lamp switch 1 toward the abutting face 21 so as to push the operating shaft 13 into the cover body 3. What is worse, since the application of a considerably large pressure is required to press the operating shaft 13 into the actuator 11 against the engagement force between the concave-convex locking portions 13a of the shaft 13 and the engaging spring 14, an operation time period becomes disadvantageously long.
In order to allow the adjustment of a projected length of the operating shaft 13 to be effectuated by only one operator, the following attachment procedure of the stop lamp switch 1 has also been conventionally taken. After the operating shaft 13 is inserted into the attachment hole 17a of the attachment bracket 17, the brake pedal 18 is pressed by the operating shaft 13 to be turned from the position indicated with the solid line in FIG. 10 to the position indicated with the double-chain line. In this manner, the stop lamp switch 1 is first fixed onto the attachment bracket 17. Thereafter, the brake pedal 18 at the position indicated with the double-chain line is returned to the position indicated with the solid line so that the operating shaft 13 whose tip abuts on the abutting face 21 of the brake pedal 18 is forced into the actuator 11 against the engagement force between the concave-convex locking portions 13a and the engaging spring 14. In this attachment method, however, one operator is obliged to have a considerable physical burden. Furthermore, there is a possibility that the attachment operation might be terminated before the operating shaft 13 is fully pushed to the predetermined position, due to physical fatigue of the operator. In such a case, an inconvenience possibly occurs in that the stop lamp may not stably lighted for each pressing operation of the brake pedal 18.
In light of the above problems, the present invention has an object of providing a stop lamp switch having such a structure that allows its easy attachment to a vehicle by only one operator and an attachment method thereof for allowing efficient and precise attachment of the stop lamp switch to a vehicle.
In order to achieve the above object, a stop lamp switch according to the present invention includes: an operating shaft penetrating through a guide hole of a switch case body so as to be outwardly projected, an end of the operating shaft on an outer side abutting on a brake pedal of a vehicle; a cylindrical actuator freely movably provided within the switch case body, for separating a movable contact from a fixed contact when the cylindrical actuator moves toward its one end side along a core direction of its cylindrical body; an approximately U-shaped engaging spring attached to the other end of the actuator so as to move integrally with the actuator, the engaging spring being engaged with a concave-convex locking portion provided on the other end side of the operating shaft so as to connect the other end of the actuator to the operating shaft; and a spring regulating member for spreading the engaging spring so as to engage both free ends of the engaging spring with engaging step portions provided to the spring regulating member in a freely engageable/disengageable manner with a reduced engagement force to the concave-convex locking portion, so that a protruding working piece provided to the spring regulating member is slidably penetrated through a through hole of a bottom wall of the switch case body to be outwardly projected. The stop lamp switch is constituted such that, after the operating shaft is inserted into the actuator so as to adjust a projected length of the operating shaft from the guide hole, the protruding working piece is pushed into the switch case body to move the spring regulating member so as to disengage both the free ends from the engaging step portions, whereby the engaging spring is engaged with the concave-convex locking portion so that the operating shaft is connected to the actuator in an integrally movable manner.
In this stop lamp switch, the operating shaft is penetrated through, for example, an attachment hole of an attachment bracket of a vehicle so as to push a tip of the operating shaft against the brake pedal at a normal position. Then, since the concave-convex locking portions of the operating shaft and the engaging spring in a spread state are held in an engaged state by a small engagement force, the operating shaft is subjected to a reaction against a pressure applied on the brake pedal so as to be smoothly inserted into the actuator. In this manner, since the application of an extremely small force is sufficient to insert the operating shaft into the actuator, the brake pedal does not move from its normal position even if the brake pedal is not held at the normal position. After a projected length of the operating shaft is adjusted to an appropriate length in this manner to complete the attachment of the operating shaft to the attachment bracket, the protruding working piece outwardly protruding from the switch case body is inwardly pushed to move the spring regulating member. Then, a pair of the free ends of the engaging spring come out from the engaging step portions of the spring regulating member so as to cancel the spread state of the engaging spring. Therefore, the engaging spring is pressed against the concave-convex locking portions of the operating shaft by a restoring force generated by the cancellation of the spread state. As a result, the operating shaft is certainly connected to the actuator with a projected length being adjusted to be at a predetermined relative position with respect to the brake pedal.
In the above-described invention, it is preferred that: the switch case body be constituted by connecting a cylindrical case having an open end with a cover body covering the opening of the case; the actuator be provided within the case so as to be freely movable in a core direction of the cylindrical case; the operating shaft be penetrated through a guide hole of the cover body; a terminal plate of a fixed contact be penetrated through the bottom wall of the case so that a terminal portion is guided into a connector connection part of the case; and the spring regulating member include: a pair of clearance holes for allowing movement of both the free ends of the engaging spring upon integral movement of the operating shaft and the actuator in an outer direction along with separation of the brake pedal from the operating shaft caused by a pressing operation of the brake pedal; and the engaging step portions, each being formed on an edge of each of the clearance holes on its one end.
With this structure, when the connector is fitted to the connector connection part so as to be connected to the terminal portions, the protruding working piece is automatically pushed into the case by the connector in the fitting operation so as to move the spring regulating member, thereby canceling the spread state of the engaging spring. Therefore, since it is not necessary to separately conduct a pushing operation of the protruding working piece, the efficiency of the attachment operation is improved. Moreover, since both the tree ends of the engaging spring, whose engagement with the engaging step portions is cancelled, move within the clearance holes of the spring regulating member when the actuator moves in such a direction that the operating shaft is projected along with the pressing operation of the brake pedal, the contact/separation of the movable contacts to/from the fixed contacts can be performed without any inconvenience.
Moreover, in the above-described structure, it is preferred that: a contact pressure spring for energizing the movable contact toward the fixed contact be interposed between the movable contact and the bottom wall of the case, and a return spring for energizing the operating shaft in such a direction that the operating shaft is projected from the guide hole be provided between the operating shaft and the bottom wall; and the cover body have position regulating pieces respectively abutting on vicinities of both the free ends of the engaging spring so as to hold the actuator in a state where the movable contact is separated from the fixed contact due to movement of the actuator, each of the position regulating pieces being provided in a projected manner at a position allowing cancellation of abutment of the engaging spring simultaneously with disengagement of both the free ends of the engaging spring from engaging portions of the spring regulating member.
As a result, when the brake pedal is separated from the operating shaft by its pressing operation, the operating shaft is moved in a projected direction due to an energizing force of the return spring. At the same time, the actuator is subjected to an energizing force of the contact pressure spring through the movable contacts so as to be moved integrally with the operating shaft. As a result, the movable contacts are surely brought into contact with the fixed contacts by the energizing force of the contact pressure spring. Even with such a structure, before the attachment, the actuator and the operating shaft can be ensured to be held at predetermined positions against the energizing force of the contact pressure spring and the return spring owing to the position regulating pieces of the cover body. Moreover, a pushing operation of the protruding working piece into the case allows the pair of free ends to return in an approaching direction due to the cancellation of the spread state of the engaging spring so that the free ends automatically come out from the position regulating pieces. As a result, the operating shaft can arbitrarily move in in/out directions to/from the cover body.
A method for attaching a stop lamp switch of the present invention is characterized by the steps of: penetrating an operating shaft of the stop lamp switch according to the present invention through an attachment hole of an attachment bracket opposing to a brake pedal of a vehicle so that a tip of the operating shaft abuts on the brake pedal; pressing the stop lamp switch against the attachment bracket until an engaging portion of the operating shaft is penetrated through the attachment hole so as to push the other end of the operating shaft into the cylindrical actuator, thereby fixing the operating shaft to the attachment bracket; and simultaneously with fitting of a connector to a connector connection part of the stop lamp switch, pressing a protruding working piece of a spring regulating member with the connector so as to push the protruding working piece into the case.
In this method of attaching the stop lamp switch, when the connector is fitted to the connector connection part, the fitted connector pushes the protruding working piece into the case so as to automatically and simultaneously cancel the spread state of the engaging spring and the stopped movement of the actuator. As a result, the efficiency of the attachment operation is improved.
While novel features of the invention are set forth in the preceding, the invention, both as to organization and content, can be further understood and appreciated, along with other objects and features thereof, from the following detailed description and examples when taken in conjunction with the attached drawings.